Ball lock and pin lock post o-rings are not all the same and may be the source of your quick disconnect/post leaks.
Ever since I got my pin lock keg and disconnects the slighest jostling of the line caused beer to leak out. The weight of the beer line alone could cause a leak at times. Large amounts of lube made the system "workable". Two weeks ago I came down to a 6 pack worth of beer all over my man cave floor. Good thing I finished the first beer quick and went for a refill before more beer was lost.
The o-rings are not more than 3 months and 10 gallons of beer old but I was so depressed I went and bought a couple pin lock o-rings from the LHBS. I took the old one out, which a vendor (who I will not name) supplied with the keg and wtf the new one is a larger size.
It seems that the ball lock and pin lock o-rings are close but not the same and many vendors supply the same one for ball and pin lock post. Changed to the new o-ring I have zero leak issues, no lube required.
Anyway this is mostly an FYI to anyone who has had a similar problem. Also as an FYI to certain vendors who do not seem to be aware there even is a difference. Hope this helps somebody and saves some beer.